Code 13 - Heated O2 Sensor Circuit

NOTE: See appropriate wiring diagram in WIRING DIAGRAMS article for terminal and connector identification.

NOTE: Test numbers refer to numbers on diagnostic chart.

1. This step checks AIR system operation:
   • Idle engine at normal operating temperature.
   • Stop engine.
   • Disconnect AIR hose at check valve and plug check valve.
   • Restart engine and idle, immediately check direction of airflow.
2. This step tests continuity of oxygen sensor circuit (Red wire) between ECM 22-pin connector terminal No. 20 and oxygen sensor.

Fig 1: Code 13 - Diagnostic Flowchart Courtesy Isuzu Motor Co